Fluid-operated percussive tool.



L. G. BAYLBS.

FLUID OPERATBD PERGUSSIVE TooL.

APPLIOATION FILED FEB. 26, 1914,

Patented May 19, 1914.

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UNITED STATES PATENT OFFICE.

LEWIS C. BAYLES, OF EASTON, PENNSYLVANIA, ASSIGNOR T INGERSOLL-RAND COMPANY, 0F JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

FLUID-.OPERATED PERCUSSI VE TOOL.

Specification of Letters Patent.

Application niet February 26,1914. serial No. 521,149.

which the? following is a specification.

' stroke.

This invention relates to fluid operated percussive tools and 'more particularly to tools of the type wherein the admission of fluid is controlled directly by the movement of the piston. The object of 'the present invention is to provide means for controlling admission of fiuid to one end of the cylinder so that the passage for conveying the fluid, althoughultimately controlled by the piston, will remain open for a greater portion of the return stroke than of the forward stroke.

This object is accomplished by thc invention, a practical embodiment of which is shown in the accompanying drawings in whicl1 Itigure's 1 and 2 are longitudinal sections showing the piston and the auxiliary Controlling valve in different positions.

In the .drawings is shown a drill having a cylinder 1 which consists of a smaller rearward bore 2 and a larger forward bore 3 in which slides a piston 4 having an enlarged iiston head 5 sliding :in the forward bore and a shank G sliding in the rearward bore, there being a neck 'Z of smaller diameter i than the shank 6 between the head and the shank. The operating fluid is admitted tol the 'rearward end of the smaller bore 2 by.

an inlet passage 8 and thus exerts a constant treme forward end of the cylinder is a passage 9 for conveying fluid to accomplish the return stroke of' the piston. This passage 9 has two portsleading from, the constant pressure portion of thc cylinder. The rearward port 10 is so placed that it is uncovered by the piston soon after the vpiston has passed the median point of its forward The forward port 11 is not uncovered until the piston is practically at the forward end o f its stroke. The port 11 `opensdirectly into the passage 9 whereas there is an auxiliary valve 12 for controlling .the port 10. This valve 12 slides in a valve chest 13 on the side of the cylinder and has a forward operating .face exposed to the pressure of lluid in passage 9 and ai rearward operating face which is exposed to the pressure of the fluid in the rear end of the cylinder bore 3 by means of a passage lei which leads therefrom to the rear end of the valve chest 13. 'lhe rear end of the bore 3 is mtermittently supplied with fluid pressure by means of a passage 15 which leads from the inlet 8 to a point near the forward end of the bore 2 so positioned as to be put into communication with `the rear end of bore il near the end of the rearward stroke of the plston by reason of the neck 7 of the piston. An exhaust port 16 is provided for the intermittently supplied parts of the cylinder, beinguncovered by the forward part of the piston near the end of its rearward stroke andafter the port 10 has been closed by the piston; and again uncovered by the rear end of the piston near the .forward end of its stroke after the-passage 15 has been closed.

1n operation, supposing the parts tobe in the positions shown in Fig. 2, thc operating fluid is being admitted by the inlet passage 8 to the constant pressure portion of the cylinder and also through the passage 15 to the rear end of the bore 3 so that there is pressure being exerted on the rear face of the piston head and on the rear face of the shank (5. Inthis position of the piston live ffluid passes through passage 14: so that there is pressure on the rear operating surface of the valve 12 and atmospheric pressure on the forward operating surface of the valve 12 by reason of the fact that the forward end of the cylinder and the passage 9 are open to atmosphere through the exhaust port 16. The valve 12 will therefore be in its forward position closing the port 1,0 J`l`he pressure of the fluid on the rearsurfaces of the piston will drive it forward, the fluid in' the bore acting expansively a'l'ter the passage 15 is out oil. By reason of the fact that the port l0 is closed by valve l2 no uid will be admitted into the front cud of the cylinder until the rear face of the piston shank (5 hasl uncovered the port 11. This will admit lluid pressure to the passage 9. The first ctlect of admission of this pressure to the passage 9 will be to drive the valve 12 rearward the're being no pressure on the rearward operating face of the valve 12 on account of the fact that the rear end of the bore 3 4is open VPatented M ay 19, 191i.

port.

The object of this construction is that -rvalthough thefluid is admitted to the for-y Wai'd .end of the cylinder `through the port 10 for the, saine period of the backward stroke as it would be if there Were novalve` 12 and thus a full return strokeof thel piston is obtained, no .fluid is admitted `to the for ward 4end of the cylinder during the forward strokeof thepiston until it hasreached approximately the forward end of itsstroke lso ythat a heavyuncushioned blow of the piston is obtained Without any increase of'tluid consumption. :Y y ,1 Y

It is' to be' understood that the present showing and v'description discloses only one specitied modification of my invention and otherforms and modifications are Iincluded in the Ispirit andscope of the claims.

What I, claim is: I, ,n I

1. In al percussive tool, a cylinder, a piston, means for ,constantly admitting yfluid to one end sof the cylinder, a passage from said constant `niessiire end of the cylinder to tthe opposi.te.eiid, said passage having a .port opening into the constant pressure end uncovered by thel piston near v,the end of its stroke, a valve closing said poi't and having. an operating surface exposed to the pres.- sure in said passage, and a second port opening to said passage fromsaid constant pressure cylinder end, said second port being uncovered by the piston at avlater point in its stroke than .said [ii-st port and serving to admit prcssureato said passage against said valveoperating" surface. to open said first 2. In apercussive.tooha eylinder,a piston in said cylinder having two small rearward surfaces and a large forward surface, means for admitting pressure constantly to a part n' ,of the cylindcrtov exert pressure on one oi" said rearward surfaces, and means for ex` crting `intermittent pressure on the other of said rearward surfaces and on said forward surface, the means -for exerting pressure, ou

`said forward surface comprising apassage leading to the forward end of the cylinder and having ay rearward port anda lforward port'ol'ieniiig into said constant pressure part of the cylinder and positioned to he"eon's'ecu tivelyl uncovered by the' piston, and a valve' adapted to close-thc rearward port.' during the forward stroke and prevent luid from entering said passage, said valve haring an operative surface exposed to the pressure in said'passage and serving to move it to open said rearward port when pressure is admitted to said passage through saidV foi'- ward port.

3. In a percussiveftool, a cylinder, a piston having two'surfaees for driving it in one direction and one surface for driving it in the other direction,` means for` admitting fluid to the cylinder to exert a constant 'ressure on one of the first. mentioned sur aces, passages lcontrolled by the piston for admitting and exhausting pressure in the cylin.

der to exert an. intermittent pressure on the second of said surfaees,- and means for exert ing intermittent pressure on ythe third surface comprising passages controlled bythe 'piston 1and a .valve having operative surfaces exposed -to the pressure on saidinterniittently supplied surfaces.

4.111 a percussive tool, a cylinder, a pis ton in said cylinder having tWo pressure surfaces for operating it in one direction and one ilarger surface for operating it in the other direction, means for admitting pressure con- 4stantlyato the cylinder, to be exerted ,onione of said smaller pressure surfaces, a passage for conveying' fluid `from tlie constant pressure part of the cylinder totlieopposite end of the cylinder to bewexertedagainst said larger surface, the saidlv passage havinga,l

port from said constant pressure party un` covered by the piston,1iear `theend offlits forward stroke, a valve .closing saidport and. haring operative surfaces, a` second f-portI from said constant pressure part adapted to be uncovered by said pistonat. a latei' period of its stroke and to admit pressure loan operating surfacevofsaid valve to open said `first port, means to admity pressure `to another `.part of the .cylinder to he exerted against the othervof said smaller. surfaces l-,during` the forward stroke of ythe piston, a

passage from said other part of the cylinder `to au operating surface of said valve .ope

posed to said first operating surface andcxhaust passages for the intermittently supplied portions of the cylinder.

` In a. permissive tool, a cylinder` means for constantly admitting pressure tofone end of the cylinder. a passage from said constant pressure end of the cylinder to the oppositie 6nd, said passage. having a port openingfinto said constant pressure end uncovered by thepiston near the end of its stroke, a valve for closing said port during the forward `stroke of the piston, said valve having an operating surface for moving it to openl said ort. a second iort o ieninr from said v constant pressure end and uncovered by said piston at a later point in its stroke, said portI serving to convey fluid pressure to said valve operating surface, and means to move said valve to close said first port on the reverse stroke ot the piston.

6. In a percussive tool, a ey'linder, u'pston in said cylinder having two pressure surfaces for operating it in one direction and one larger" surface for operating it in the other dn'eeton, Ineens for udnnlting pres sure constantly tothe cylinder to be exerted on one of Suid snmller `pressure surfaces, :L passage `for conveying fluid from the eonstant pressure part of the cylinder to the op posite end of the cylinder tov be exerted against said larger surfmze, the said passage having a port from said constant pressure part uncovered by the piston near the enrfl of its forwurd stroke, :1 valve closing said portnndhnvng operative Surfaces, u second port; from said constant, pressure part .of the vulve to close Suid port on the lmek stroke of the piston. I

In testuuony whereot, I have hereunto set my hund. t

LEWIS C. BAYLES.

WiV n t tussen, H. WILHELM. 

